Guidewires are typically used to navigate the vasculature of a patient during intracorporeal procedures. Once the guidewire has been introduced, it may then be used to introduce one or more medical devices. Conventional guidewires are typically about 0.014-0.038 inches in diameter and have a lubricous coating to enhance guidewire introduction and movement. These conventional “floppy” guidewires have sufficient flexibility and torque control for navigation through tortuous vessels.
It has been estimated that a third to a half of patients presenting coronary disease from angiograms have at least one chronic total occlusion (CTO). However, conventional guidewires often lack sufficient tip stiffness or pushability to traverse the tough fibrous proximal and distal caps in a CTO, particularly when contralateral intervention procedures are employed to reach a distant CTO. In such cases, a physician may introduce a catheter through a femoral artery to access the lower leg, which necessarily increases the working length of the guidewire. Where there is a need to traverse an occlusion, such as a CTO in a peripheral or coronary artery, pushability of the device from the access site cannot provide a sufficient or predictable amount of force through the occluded region to facilitate further interventional procedures. Indeed, the major determinant of success for angioplasty of CTOs is ability to pass a guidewire across the lesion. Accordingly, there exists a need for improving the ability to maneuver a guidewire and/or catheter through lesions in distal regions of a patient's vasculature.